Parallel wheel drive

ABSTRACT

Devices for driving the propulsion wheels of a unit carrier system in which a plurality of cars are driven over a trackway by means of the frictional interaction of reaction surfaces on the cars with propulsion wheels mounted in the trackway. The devices consists of drive motors connected to a plurality of propulsion wheels by means of belts, chains, etc.

Ultited States Patent 1191 Armstrong June 25, 1974 [54] PARALLEL WHEEL DRIVE 3.643.788 2/1972 Werntz 198/127 R [75] Inventor: Larry C. Armstrong, Ellwood City,

p Primary ExammerM. Henson Wood, Jr. Assistant Examiner-D. W. Keen [73] Ass1gnee: Rexnord lnc., M1lwaukee, WIS. Attorney, Agent, or Firm-Sughrue,iRothwell, Mion, 221 Filed: Nov. 24, 1972 Zmn & p

[21] Appl. No.: 309,027

[57] ABSTRACT 52 US. (:1. 104/168, 198/127 R Devices for driving the propulsion wheels of a n [51] Int. Cl B61b 13/00 carrier System in which a plurality of Cars are driven 5 Field of Search 104/18, 20, 23, over a trackway by means of the frictional interaction 1 193/110, 127 R of reaction surfaces on the cars with propulsion wheels mounted in the trackway. The devices consists 5 References Cited of drive motors connected to a plurality of propulsion UNITED STATES PATENTS wheels by means of belts, chains, etc. 2,905,101 9/1959 i-Sinden 104/20 2 Claims, 4 Drawing Figures ,1 1 91111111. llHW' lH 11 1!" i/Wml t I 1 PARALLEL WHEEL DRIVE FIELD OF THE INVENTION This invention relates generally to the transmission of power to the propulsion wheels in a friction-powered unit transportation system and, more specifically, to

a transportation system such as is disclosed in commonly assigned U.S. Pat. Nos. 3,621,790, 3,626,859, and 3,650,216.

BACKGROUND OF THEINVENTION In a friction-powered unit transportation system such as is disclosed in U.S. Pat. No. 3,626,859, a plurality of cars are driven over a trackway by means of the frictional interaction of reaction surfaces on the cars with propulsion wheels mounted in the trackway. In the system disclosed in that patent, each propulsion wheel is provided with its own drive motor, which may be identical, constant-speed induction motors since the speed of the cars is controlledby varying the angle between the axis of the propulsion wheel and the direction of the track. This arrangement offers great flexibility, but the induction motors are relatively expensive, and the flexibility which this arrangement-offers is not needed in all situations.

SUMMARY OF THE INVENTION In areas of the unit carrier system where the flexibility offered by the arrangement described in commonly assigned U.S. Pat. No. 3,626,859 is not needed, a plurality of propulsion wheels may be driven by a single drive motor connected to the propulsion wheels by means of belts, chains, and the like. This arrangement *is particularly adapted for long, straight sections of the trackway, but it may also be used oncurves with the aid of ancillary devices disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE PREFERRE EMBODIMENTS For illustrative purposes, two species of the generic invention are disclosedherein. The first to be described employs v-belts and sheaves and may be adapted for use on curved sections of the trackway. The second employs a flat belt which engage directly with the work surface of the propulsion wheels; it is somewhat simpler than the first species, but it is not as well adapted for curves.

The first species is illustrated in FIGS. 1 and 2. As shown therein, the motor 10, which may be a constant speed induction motor such as is used in the arrangement described in commonly assigned U.S. Pat. No. 3,626,859, is mounted on supports 11 and 12 which are bolted to the cross ties 13 of the tracks 14. The motor is mounted low in the trackway, clear of any possible interference with the bottoms of the cars (not shown). The motor 10 rotates a sheave 15, which en- I the transmission of power to the propulsion wheels in I gages a v-belt 16 which also engages a sheave 17 which is co-axially mounted with a propulsion wheel 18. The

propulsion wheel 18 is mounted on a cross tie l3, and the sheave ,17 has two other grooves in addition tothe groove which engages v-belt 16. One of those other grooves engages a second v-belt 19, which engages an idler sheave 20 movably mounted to take up any slack in the v-belt 19 and another sheave and propulsion wheel unit, which is mounted off to the left of the drawings. The other groove engages a third v -belt 21, which engages a sheave 22 which is coaxially mounted with propulsion wheel 23. It should be noted that the workingsurface of propulsion wheel 23 is broader than the working surface of propulsion wheel 18 because propulsion wheel 23 is mounted just before a switch, which means that the reaction surface of the cars taking the siding (i.e., the right-hand branch in FIG. 1) will contact its working surface at an angle.

The sheave 22 also has two other grooves in addition to the groove which engages v-belt 21. One of these engages v-belt 24, which engages another sheave and propulsion wheel unit 25, mounted in the through track. This unit is connected to another, mounted off to the right of the drawings, and so on to the limit of the motors power. However, it should be noted that, if the power is to be transmitted on down the through track in this manner, the v-belt will have to be passed underneath the left-hand track 14 of the siding, which may often be impractical, or at least not worth the effort. The other groove on sheave 22 engages a v-belt 26 which passes over a tension bracket assembly 27 before engaging a sheave 28 coaxially mounted with propulsion wheel 29 mounted in the siding. The tension bracket assembly 27 is mounted on a support 30 which is attached to two cross-ties 13 by any suitable means, and its purpose is to change the direction of the v-belt 26, so that the linear force it exerts on both sheave 22 and sheave 28 is normal to their respective axes. While this configuration is illustrated here in connection with a switch, it will be obvious that it will be most frequently employed in connection with a curved portion of a single trackway. This is because of the previously mentioned inconvenienceof passing the v-belt under the near track of a diverging trackway.

The second species of the generic invention is illus trated in FIGS. 3 and 4. As shown therein, the motor 40, which may again be a constant speed induction motor such as is used in the arrangement described in commonly assigned U.S. Pat. No. 3,626,859, is mounted on supports 41 and 42 which are bolted to the cross ties 43 of the tracks 44. The motor 40 is mounted low in the trackway, clear of any possible interference with the bottoms of the cars (not shown). It rotates a sheave 45 which engages a plurality of v-belts 46 which also engage a sheave 47 which is co-axially mounted with a pulley 48. The pulley 48 is rotatably mounted on rear support 42 and drive frame member 49, which are braced at intervals by cross members 50. The working surface of the pulley 48 transmits its rotary motion to flat belt 51, and flat belt 51 in turn transmits this motion to propulsion wheels 52, which are also rotatably mounted on rear support 42 and drive frame member 49. Idler rollers 53 and 54, which are also rotatably mounted on rear support 42 and drive frame member 49, are provided, respectively, to lift the path of the flat belt 51 up over the cross ties 43 and to cause the flat belt to contact the propulsion wheels over van arc,

thereby insuring good frictional contact between the flat belt 51 and the propulsion wheels 52. The flat belt 51 is shown rising towards another idler pulley 54 at the left edge of the drawing, and it will be obvious that is can power as many propulsion wheels 52 as the power rating of the motor 40 permits. Tension in the flat belt 51 can be regulated by take-up pulleys (not shown) in a manner well known in the art.

CAVEAT While the present invention has been illustrated by detailed descriptions of two preferred embodiments thereof, it will be obvious to those skilled in the art that various changes in form and detail can be made therein without departing from the true scope of the invention. For instance, (I) the v-belts disclosed in connection with the first species could be replaced by round belts, chains, ropes, or any similar linear drive means, (2) a pulley could be mounted directly on the shaft of a drive motor, thereby eliminating the v-belts and sheaves shown in the second species, and (3) while the illustrations show constant speed drive systems, the peripheral speed of the various propulsion wheels can be varied by varying the diameter of the wheels themselves and the sheaves or the pulleys, all in a manner well known to the art. For that reason, the invention must be measured by the claims appended hereto and not by the foregoing preferred embodiments.

What is claimed is:

1. In a friction-powered unit carrier system having a plurality of cars which travel along trackways and are powered by the interaction of reaction surfaces on the cars with propulsion wheels mounted in the trackways, a device for transmitting power to said propulsion wheels comprising:

1. a drive motor mounted in a trackway;

2. a plurality of propulsion wheels;

3. linear drive means operatively connecting said drive motor to said propulsion wheels; and

4. a tension bracket assembly for changing the direction of said linear drive means.

2. A friction-powered unit carrier system as claimed in claim 1 wherein said linear drive means are v-belts connecting sheaves rotably mounted onsaid motor and coaxially and integrally mounted with' said propulsion wheels. 

1. In a friction-powered unit carrier system having a plurality of cars which travel along trackways and are powered by the interaction of reaction surfaces on the cars with propulsion wheels mounted in the trackways, a device for transmitting power to said propulsion wheels comprising:
 1. a drive motor mounted in a trackway;
 2. a plurality of propulsion wheels;
 3. linear drive means operatively connecting said drive motor to said propulsion wheels; and
 4. a tension bracket assembly for changing the direction of said linear drive means.
 2. a plurality of propulsion wheels;
 2. A friction-powered unit carrier system as claimed in claim 1 wherein said linear drive means are v-belts connecting sheaves rotably mounted on said motor and coaxially and integrally mounted with said propulsion wheels.
 3. linear drive means operatively connecting said drive motor to said propulsion wheels; and
 4. a tension bracket assembly for changing the direction of said linear drive means. 